Torquer commutator



March 21, 1967 s. c. HANNA ETAL 3,310,694

TORQUER COMMUTATOR Filed Oct. 26, 1964 SAMUEL C. HANNA HERBERT BiNDER WILLIAM D4 JOHNSON INVENTORS ATTORNEY United States Patent 3,310,694 TORQUER COMMUTATOR Samuel C. Hanna, Saddle Brook, Herbert Binder, New

Monmouth, and William D. Johnson, Franklin Lakes,

N.J., assignors to General Precision Inc., Little Falls,

NJ., a corporation of Delaware Filed Oct. 26, 1964, Ser. No. 406,426 2 Claims. (Cl. 310-154) The present invention relates to permanent magnet D.-C. torquers for gyroscopes and inertial platforms, and more particularly to: a permanent magnet D.-C. torquer having a commutator with preformed, integral, lead wires.

A conventional D.-C. torquer has a permanent. magnet ring. with contact brushes mounted on one wall of a housing which is rotatable relative to a coil-wound armature ring and a printed-circuit commutator ring mounted on another housing wall. The commutator ring has a plurality of commutator bars connected to the coils of. the armature. Each commutator bar has a soldered connection to one end of a lead wire. Each lead wire has an opposite end with a soldered connection to two of the coils.

One problem with such a conventional D.-C. torquer is the possibility of connection failures, particularly because of the large number of connections. For example, a conventional 12-pole torquer often has 49 commutator bars having 49 lead wires with 98 soldered connections. Reliability can be greatly increased. by reducing the number of such connections.

In accordance with one embodiment of the present invention, one-half of such soldered connections are eliminated and all said lead wires are eliminated by using a printed-circuit laminate comprising a washer-shaped insulating board and elongate metal-foil strips with only their end portions bonded to the board. Such strips are also preformed in an L-shape forming a subassembly having an annular cavity for receiving the armature ring.

Accordingly, it is one object of the invention to increase the reliability of a D.-C. torquer by minimizing the number of its commutator connections.

It is another object of the invention to increase the reliability and to minimize the number of parts in a DC. torquer by eliminating separate lead wires between its commutator and its coils.

It is a further object of the invention to increase the reliability and to minimize the number of parts in a D.-C. torquer by supporting the commutator from the armature itself without extra support bands therebetween.

' To the fulfillment of these and other objects, the invention provides a spider-shaped commutator for a D.-C. torquer comprising a washer-shaped insulation board with an axis of symmetry and a face normal thereto, and a plurality of L-shaped, peripherally-spaced metal strips having radial leg portions parallel to and bonded to said board face and having axial leg portions normal to and extending away from said board face and haivng bent intermediate portions interconnecting said legs.

Other objects of the invention will become apparent upon reading the annexed detailed description in connection with the drawings wherein like parts are designated by like numerals throughout the several views, and wherein:

FIG. 1 is a sectional view of a D.-C. torquer;

FIG. 2 is a sectional view taken along line 22 of FIG. 1;

FIG. 3 is an enlarged view of a portion of FIG. 1;

FIG. 4 is a sectional view taken along line 44 of FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 3; and

FIG. 6 is a sectional view taken along line 66 of FIG. 3.-

Referring to: the drawings, one embodiment of the present. invention is a torquer 10 comprising a stationary' support member 12 with a plurality of magnets 20 and a pair of brushes 58, 60, and a housing 28 rotatable thereto with an armature 40 and a commutator 52. A torquer of this general type: is described in US. Patent No- 3,178,599, assigned to the same assignee as in this invention.v Torquer 10 is preferably a D.-C'. permanent magnet torquer.

Support. member 12,. which iscomposed of permeable material, has an inner cylindrical wall 14 with an axis 15,. a coaxial, outer cylindrical, return-path wall 16 and a coaxial, washer-shaped, end wall 18.

Magnets 20, which. are permanent-type pole pieces, and which are supported on. wall 12, are mounted on the radially outer side of. wall 16... There are preferably 12 magnets in. embodiment 10 forming a l2-pole magnet subassembly. Wall14 has a concentric bearing 22,. which is clamped between. ashoulder 24 on wall 14 and its adjacent bearing nut.26.

Rotatable housing 28 issupported by wall 12. and bearing 22. Housing 28, which. is also composed of permeable material, and which is coaxial with stationary support member 12 along axis. 15', has an inner cylindrical Wall 30, an outer cylindrical wall 32 and a washer-shaped end wall 34. Wall 30 has a lip 36 and has an adjacent nut or snap ring 38 for connecting bearing 22 to wall. 30.v

Armature 40, which is supported by housing 28, is a.

has 49 of said slots 44, and 49. of. said coils 46, which.

cooperate with said 12 magnets 20.

commutator 52 is supported by armature ring 42, and abuts wall 34, and is coaxial with ring 42 along axis 15.

Brushes 58, 60, which are supported by magnets 20, are connected to a support ring 62 which. is cemented to the axially outer faces of magnets 20. Brush 58 is located at the twelve oclock position in FIG. 2 and conducts current to commutator 52; and brush 60 is located near to the six oclock. positionv in FIG. 2 for ease of illustration and conducts current from commutator 52. Brush 58 has a supply lead 64 and brush 60 has a return. lead 66. Brushes 58, 60 are preferably spring-supported with silver-graphite contact faces.

Coils 46 are each composed of a plurality of turns of a strand of continuously-wound filament wire; and said coils 46 are connected in series. Each. coil 46- encircles four poles and overlaps, four adjacent coils. Each coil has a filament end portion 68 (FIG. 4), which is connected to a. filament beginning portion 70 of a subsequent coil in its series.

Member 12 also has a cover 73, which is removably mounted on the radially outer side of wall 16; the cover 73 has a slot 71 through which leads 64 and 66 pass into the housing.

The, construction ofv torquer 10. is more. fully described in the aforementionedUS. applicationv Ser. No. 168,061.

According to the invention, commutator 52, which has a spider-shape, and which is coaxial with armature 40 along axis 15, has a washer-shaped insulation ring 72, that backs up a plurality of L-shaped commutator bars 74 that are bonded to ring 72.

Bars 74, which are equally spaced in a peripheral direction about axis 15 and which are preferably made of printed-circuit, metal-foil strips, have respective radial leg portions or legs 76, pointing in a radially inward direction toward axis 15, and have axial leg portions or legs 78, pointing in a direction substantially parallel to axis 15, and have intermediate portions 80, bent in an L-shape, interconnecting said legs 76 and 78.

Legs 76 have outer sides 82, which are disposed in a plane substantially at right angles to axis 15, and which face in an axially outward direction. Legs 76 also have inner sides 84, which are respectively parallel to sides 82 and bear against the adjacent faces of brushes 58, 60. Legs 76 are spade-shaped or trapezoidal in profile with enlarged peripheral widths for providing sides 84 with enlarged brush-contact surfaces.

Legs 78 are respectively received with frictional engagement in slots 44 thereby supporting commutator 52 from armature 40 and eliminating extra support band insulators therebetween, and also providing a novel commutator-armature structure. Legs 78 respectively make three-way connections 86 with coil ends 68, 70, said connections 86 being disposed within slots 44 for ease of insulation and for supporting said connections against vibration forces. In this way, separate lead wires as required in the prior-art type of torquer, extending from the coilend connections through the slots to the commutator, can be eliminated. In addition, pairs of soldered connections, one pair for each said lead wire in the prior-art type of torquer, can also be eliminated. With the construction of torquer 10, 49 extra lead wires with 49 extra soldered connections have been eliminated as compared to the prior-art type of torquer. In this way, torquer 10 has an improved reliability and a reduced cost. Legs 78 also have outer faces 88, which face in a radially outward direction for ease of applying solder 87, or the like, to coil ends 68, 70 and to faces 88 for making connections 86.

Ring 72 has a ring face 90 to which sides 82 of legs 76 are cemented. With this construction, commutator 52 is a bowl-shaped subassembly structure with a rigid-frame cross-section. Ring 72 is preferably also cemented to wall 34 for additional support against vibration.

Intermediate portions 80 preferably also have insulation covers or coats 92 which are preferably bonded to the exterior surfaces thereof for insulating portions 80 from ring 42 and walls 32, 34. Coats 92 are composed of heat-resistant, electrically-insulating material, such as epoxy resin, or the like.

Filaments 68, 70 and bars 74 are also wrapped in insulating sheets 94 along those portions thereof which are disposed within slots 44 for insulating connections 86. Sheets 94 also insulate portions of coils 46 disposed in said slots, and assure a snug fi-t of leg portions 78 within slots 44. Coils 46 also have cast insulation 96, which covers all portions of said coils 46 within and on the exterior of slots 44. Insulation 96 has portions in the form of two annular rings disposed against the axially outer sides of armature 40. Bars 74 are fitted against the outer surface of an adjacent portion of insulation 96 (FIG. 3) for minimizing relative movement between commutator 5-2 and armature 40, and for providing a rigid commutator-armature assembly.

The preferred method of manufacture of commutator 52 is as follows:

(*1) Bond a fiat, washer-shaped sheet of copper coil to the face of a washer-shaped insulating board, which has substantially the same inside diameter but a smaller outside diameter than said metal-foil sheet.

(2) Using a conventional printed-circuit manufacturing process, such as an etching process, remove or etch a pattern of equal-spaced radial spaces in said metal-foil sheet thereby leaving a plurality of equal-spaced radial metal-foil strips, with the radially inner portions of said strips supported by said insulating board.

(3) Pre-form the flat metal-foil strips to L-shaped metal-foil strips having radial legs substantially parallel to the plane of said board face and bonded thereto, and having axial legs substantially normal to the plane of said board face and extending outwardly from said face.

In summary, torquer has increased reliability as compared to prior-art torquers because the number of its commutator connections have been minimized. Torquer 10 has fewer parts and more reliability than prior art torquers because extra lead wires between its com mutator and its coils have been eliminated, and in addi tion, because extra support bands disposed between its commutator and its armature have also been eliminated. Torquer 10 also has increased reliability because its commutator-coil connections have been provided with vibration-resistant mountings.

While the present invention has been described in a preferred embodiment, it will be obvious to those skilled in the art that various modifications can be made therein within the scope of the invention. For example, axial legs can be disposed on the radially inward side of their insulating ring, for use in a torquer of the type which has its magnet ring disposed on the radially outer side of its coil-wound armature ring. In addition, a dual commutator can have two sets of radially-separated, L-shaped bars. It is intended that the appended claims over all such modifications.

What is claimed is:

1. In a D.-C. torquer of the inside-out type having an annular permanent magnet ring with an axis and having a plurality of magnetized poles peripherally spaced about said axis;

a pair of brushes mounted on said magnet ring with faces in a plane substantially at right angles to said axis; and

an armature ring rotatable relative to said magnet ring about said axis and having a plurality of coll-wound poles peripherally spaced about said axis with slots between said poles, the armature poles being sepa-- rated from said magnet poles by a substantially constant gap; the improvement therein comprising a spider-shaped commutator ring coaxial with said armature and magnet rings and mounted on said armature ring having a washer-shaped insulation board with a face substantially parallel to the plane of said brush faces, and having a plurality of L shaped metal commutator bar's peripherally spaced about said axis, said bars having radial legs bonded to said board face for contacting said brushes and having axial legs snugly received in said slots and connecting to said armature coils.

2. A D.-C. torquer, comprising a stator of permeable material having an inner cylindrical wall and an outer cylindrical wall interconnected by a washer-shaped end 'wall,

a bearing surrounding said inner cylindrical wall with the inner race thereof fixed to the Wall, plurality of permanent bar magnets circumfer'entially' spaced about and projecting from said outer cylin= dri-cal wall with their poles aligned radially, rotatable housing of permeable material having an inner cylindrical wall and an outer cylindrical Wall interconnected by a washer-shaped end wall, the inner cylindrical wall of said housing being fitted about and secured to the outer race of said bearing with the outer cylindrical wall of the housing extending about and radially spaced from the exposed poles of said magnets, laminated armature ring with radial teeth separated by slots surrounding the exposed poles of said magnets to define an air gap thereabout and being secured within said outer cylindrical wall of the housing for rotation therewith, plurality of coils wound on said teeth and circumferentially disposed on said armature ring having connections disposed in said slots and having radially aligned axes, and commutator means for controlling the direction of. current flow through said coils in response to the position of the coils relative to the magnets,

. 5 Y 6 said commutator means including a washer-shaped in- References Cited by the Examineiifiii iiilidi h fiffigii$ZQSZ%$ZLL? UNITED STATES PATENTS I u s 1 i washer-shaped end wall of said rotatable housing, 1464184 8/1923 'Mansben'del 3'10i233 X and including .a plurality of L-shaped metal com- 5 2861203 11/1958 Lunem et a1 310.435 X m-utat-or bars having radial legs bonded to said in- 3,178,599 4/1965 Kruplck at 310 154 snlating board and having axially-parallel legs extending into said slots and conne'cting to said coil MILTON HIRSHFIELD Pnmary Exammer' connections disposed within said slots. D. F. DUGGAN, Assistant Examiner. 

2. A D.-C. TORQUER, COMPRISING A STATOR OF PERMEABLE MATERIAL HAVING AN INNER CYLINDRICAL WALL AND AN OUTER CYLINDRICAL WALL INTERCONNECTED BY A WASHER-SHAPED END WALL, A BEARING SURROUNDING SAID INNER CYLINDRICAL WALL WITH THE INNER RACE THEREOF FIXED TO THE WALL, A PLURALITY OF PERMANENT BAR MAGNETS CIRCUMFERENTIALLY SPACED ABOUT AND PROJECTING FROM SAID OUTER CYLINDRICAL WALL WITH THEIR POLES ALIGNED RADIALLY, A ROTATABLE HOUSING OF PERMEABLE MATERIAL HAVING AN INNER CYLINDRICAL WALL AND AN OUTER CYLINDRICAL WALL INTERCONNECTED BY A WASHER-SHAPED END WALL, THE INNER CYLINDRICAL WALL OF SAID HOUSING BEING FITTED ABOUT AND SECURED TO THE OUTER RACE OF SAID BEARING WITH THE OUTER CYLINDRICAL WALL OF THE HOUSING EXTENDING ABOUT AND RADIALLY SPACED FROM THE EXPOSED POLES OF SAID MAGNETS, A LAMINATED ARMATURE RING WITH RADIAL TEETH SEPARATED BY SLOTS SURROUNDING THE EXPOSED POLES OF SAID MAGNETS TO DEFINE AN AIR GAP THEREABOUT AND BEING SECURED WITHIN SAID OUTER CYLINDRICAL WALL OF THE HOUSING FOR ROTATION THEREWITH, A PLURALITY OF COILS WOUND ON SAID TEETH AND CIRCUMFERENTIALLY DISPOSED ON SAID ARMATURE RING HAVING CONNECTIONS DISPOSED IN SAID SLOTS AND HAVING RADIALLY ALIGNED AXES, AND COMMUTATOR MEANS FOR CONTROLLING THE DIRECTION OF CURRENT FLOW THROUGH SAID COILS IN RESPONSE TO THE POSITION OF THE COILS RELATIVE TO THE MAGNETS, SAID COMMUTATOR MEANS INCLUDING A WASHER-SHAPED INSULATING BOARD ENCIRCLING THE INNER CYLINDRICAL WALL OF SAID ROTATABLE HOUSING BETWEEN SAID MAGNETS AND SAID WASHER-SHAPED END WALL OF SAID ROTATABLE HOUSING, AND INCLUDING A PLURALITY OF L-SHAPED METAL COMMUTATOR BARS HAVING RADIAL LEGS BONDED TO SAID INSULATING BOARD AND HAVING AXIALLY-PARALLEL LEGS EXTENDING INTO SAID SLOTS AND CONNECTING TO SAID COIL CONNECTIONS DISPOSED WITHIN SAID SLOTS. 